Population change map

#> `summarise()` has grouped output by 'basin_country', 'COUNTRY', 'BASIN_NAME'.
#> You can override using the `.groups` argument.

Use the interactive map below to check population changes. Zoom in to see where Podocnemis unifilis is Endangered based on IUCN Red List criteria - A3bd.

• Overall Podocnemis unifilis is Endangered (“Em perigo” / “En peligro”) based on future population size reduction criteria - A3bd.
  Within 3 generations (35 years) the adult female population is predicted to decline by 50.6% in the future (25 and 75% quantile range: 64.7 - 34.4 % decline).

Map

If you find any errors (e.g. points where Podocnemis unifilis does not occur, points where species is “Endangered” but populations are increasing etc) please raise an issue at: https://github.com/darrennorris/TACAR/issues .

• When you zoom in you will see shaded points.
  The points are brown where populations are predicted to decline by 50% or more within 3 generations (35 years). Brown points therefore represent rivers where the species is Endangered (“Em perigo” / “En peligro”), following the IUCN Red List population size reduction criteria - A3bd (https://www.iucnredlist.org/about/faqs).

• The points follow rivers mapped by remote sensing. This standardized global scale mapping comes from Grill et al 2019, Free-flowing Rivers: https://doi.org/10.1038/s41586-019-1111-9. The points are locations along rivers selected to represent where Podocnemis unifilis females are likely to nest and that are likely to be accessible to people by boat. To facilitate online viewing the mapped points are a subset at intervals of approximately 10 kilometers.

• Due to the number of points, the map can become slow to respond when you zoom in.
  If this happens, zoom out to a level showing fewer points and you can pan around the map to find the area of interest. Then zoom in again to check the coloured points.

• This is a conservative (best-case) estimate.
  Endangered (A3bd), is threfore a precautionary IUCN Red List assessment.

  • Important threats are not included (e.g. land use change).
  • Losses are potentially buffered by an overly generous 20% ceiling to increases in unaccesible populations.
  • Population projections use the earliest likely breeding age.
  • Hunting of adult females was limited to 10% per year in the most pessimistic scenarios.
  • HUnting accessibility was limited to a distance of 50 km. This will underestimate impacts associated with threats such as large scale harvest around urban areas (Chaves et. al. 2021).

Methods

The analysis is developed here: https://github.com/darrennorris/TACAR, The methods used are an extension of Norris et. al. 2019 that includes:

• Stochastic population projections.
• Future impacts to populations caused by human acessibility (hunting) and actions that reduce river connectivity.